Mask system

ABSTRACT

A mask assembly for a patient includes a frame having a lateral flange portion with at least a first hole therethrough. The mask assembly further includes a cushion having a lateral flange portion with at least a second hole therethrough. In addition, the mask assembly includes a cushion clip having a lateral flange with at least one rod that passes through the first and second holes, the rod having a distal end that is secured to the frame when the rod passes through the first and second holes, to thereby sandwich the cushion flange between the flanges of the frame and the cushion clip.

CROSS-REFERENCE TO APPLICATIONS

This application is a continuation of U.S. application Ser. No.13/110,281, filed May 18, 2011, now allowed, which is a divisional ofU.S. application Ser. No. 10/585,091, filed Jun. 30, 2006, now U.S. Pat.No. 7,967,013, which is the U.S. national phase of InternationalApplication No. PCT/AU2004/001813, filed Dec. 22, 2004 which designatedthe U.S. and claims priority to U.S. Provisional Application Nos.60/533,229, filed Dec. 31, 2003, 60/571,488, filed May 17, 2004,60/588,341, filed Jul. 16, 2004, and 60/619,022, filed Oct. 18, 2004,and International Application No. PCT/AU2004/001760, filed Dec. 15,2004, each of which is incorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a disposable mask system for use withpatients, e.g., adult patients, for the treatment of obstructive sleepapnea (OSA) or the provision of non-invasive positive pressureventilation (NIPPY) support using continuous positive airway pressure(CPAP), bi-level, or other pressure support ventilators. The mask isintended for single patient, short-term use having a life span, e.g., ofabout 7-14 days. Preferably, the mask is only usable for up to 7 days.

2. Description of Related Art

ResMed's Mirage® Disposable Full Face mask is formed of a frame with adouble wall silicone cushion. The cushion, elbow, and/or vent componentscan be disassembled from the frame. While this mask performs stronglyfor seal and comfort, it may not display characteristics that are mostamenable for hospital and clinical use, which can differ from thecharacteristics most suitable for home or other uses.

Another related art disposable mask is ResMed's Disposable Nasal Mask®which has a PVC bubble cushion and a styrene frame. The Image3Disposable Full Face Mask from Respironics has a frame and a siliconecushion. Yet another full face disposable mask is the RespironicsSpectrum Disposable Full Face Mask that has a single PVC cushion and aframe. The Med Series 2100 Disposable Full Face Mask has a PVC frame anda foam cushion. Still another mask is the “Performa Trak,” a single usefull face mask from Respironics.

These related art masks do not provide fully adequate and/or optimumsolutions for use of mask systems in a hospital or clinical environment.For example, these masks exhibit one or more properties that aretypically associated with re-useable masks. Therefore, these masks canbe accidentally re-used in a manner that could be dangerous to thepatient, e.g., the risk of spread of germs, etc.

BRIEF SUMMARY OF THE INVENTION

One aspect of the invention is to provide a mask system which is atleast partially capable of overcoming the problems of the related art.

Another aspect of the invention is to provide a disposable mask whichhas a useful life of either a single use or can be used over a shortperiod of time, e.g., 7-10 days or more. Preferably, the mask can beused only up to 7 days.

Another aspect of the invention is to provide a mask which provides anindication, e.g., a visual indication, that the mask has been used once,more than once or more than the recommended number of times or period oftime.

Yet another aspect of the invention is to provide a mask assembly whichis difficult to disassemble without breaking, thereby discouragingmultiple use and preventing removal of safety components such as ananti-asphyxia valve.

Still another aspect of the invention is to provide a mask which isdisposable and/or which satisfies the needs of the clinical or hospitalenvironment, which often differ from the needs of a mask used in a homeenvironment.

In another aspect, the mask is designed to be fitted by a clinician ornurse.

Another aspect of the invention is to provide a low cost mask with highdifferentiation between disposable and reusable products, in terms offunctionality, aesthetics and/or durability.

These and other aspects of the present invention are described in orapparent from the following description of preferred embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view from the front left side illustrating afirst preferred embodiment of the present invention;

FIG. 2 is a rear view thereof;

FIG. 3 is a front perspective exploded view of a portion of the assemblyshown in FIG. 1;

FIG. 4 is a rear perspective exploded view of a portion of the assemblyshown in FIG. 1;

FIG. 5 is a bottom view of the mask assembly shown in FIG. 1;

FIG. 6 is a top view thereof;

FIG. 7 is a right side view thereof;

FIG. 8 is a perspective view of a frame according to an embodiment ofthe present invention;

FIG. 9 is a rear view thereof;

FIG. 10 is a top view thereof;

FIG. 11 is a bottom view thereof;

FIG. 12 is a side view thereof;

FIG. 12A is a perspective view of a frame according to anotherembodiment of the present invention;

FIG. 13 is a front perspective view of a cushion according to thepresent invention;

FIG. 14 is a front view thereof;

FIG. 15 is a rear view thereof;

FIG. 16 is a rear perspective view of a cushion clip according to thepresent invention;

FIG. 17 is a side view thereof;

FIG. 18 is a partial exploded cross-sectional view showing assembly ofthe frame, cushion and cushion clip;

FIG. 19 is an assembled partial cross-sectional view thereof;

FIG. 20 is a partial exploded cross-sectional perspective view like thatshown in FIG. 18;

FIG. 21 is an exploded perspective view of a swivel elbow assemblyaccording to the present invention;

FIG. 22 is an assembled view thereof;

FIG. 23 is a cross-sectional view thereof;

FIG. 23A is an enlarged detail view of a portion of FIG. 23;

FIG. 23B is a perspective and cross-sectional view of an elbow accordingto an embodiment of the invention;

FIG. 24 is a rear perspective view of a swivel elbow according to anembodiment of the present invention;

FIG. 25 is a front perspective view thereof;

FIG. 26 is a rear view thereof;

FIG. 27 is a bottom view thereof;

FIG. 28 is a side view thereof;

FIG. 28A illustrates a perspective view of a swivel elbow according toanother embodiment of the present invention;

FIGS. 28A-1-28A-2 illustrate views of an elbow according to stillanother embodiment of the present invention;

FIGS. 28B-28C illustrate views of an elbow according to an alternativeembodiment of the present invention;

FIGS. 28D-28H illustrate views of an elbow according to yet anotherembodiment of the present invention;

FIG. 29 is a front perspective view of an anti-asphyxia valve membraneaccording to the present invention;

FIG. 30 is a front view thereof;

FIG. 31 is a side view thereof;

FIGS. 31-A to 31-I illustrate a mask assembly, elbow, swivel and/oranti-asphyxia valve member in accordance with an embodiment of thepresent invention;

FIG. 32 is a front view of a headgear clip according to the presentinvention;

FIG. 33 is a perspective view thereof;

FIG. 34 is a rear view thereof;

FIGS. 34A and 34B illustrate front and rear perspective views of aheadgear clip according to another embodiment of the present invention;

FIG. 35 illustrates a perspective view of headgear according to oneembodiment of the present invention;

FIG. 36 is a front perspective view of the headgear of FIG. 35 inposition on a human head;

FIG. 37 is a rear perspective view of the headgear of FIG. 35 on a humanhead;

FIG. 38 illustrates yet another embodiment of headgear according to thepresent invention;

FIG. 39 illustrates the headgear of FIG. 38 from front perspective viewon a human head;

FIG. 40 illustrates the headgear of FIG. 38 in rear perspective view ona human head;

FIG. 41 illustrates a perspective view of headgear according to stillanother embodiment of the present invention; and

FIG. 42 is a perspective view of the headgear of FIG. 41 on a modelpatient's head.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Preferred embodiments of the present invention will be described inrelation to the appended figures, in which like reference numerals referto like parts.

FIG. 1 shows a mask assembly 10 which includes a frame 12 in the form ofa shell, and a cushion 14 that is provided, e.g., attached, to the frame12. A swivel elbow 16 is rotatably coupled or provided to the frame 12.The swivel elbow 16 includes an inlet conduit 18 that receivespressurized breathable gas from a suitable source of pressurized air, asis known in the art. The swivel elbow 16 includes one or more apertures20 which serve to continually wash out exhaled CO₂ gas from a breathingchamber formed by the frame 12 and the cushion 14. The frame 12 includesat least a pair of lateral outriggers 22 which support connector clipreceptacles 24 designed to receive connector clips (see, e.g., FIGS.32-34) associated with headgear (see, e.g., FIGS. 35-40). The frame 12includes a centrally located upper extension 38 including variousstructure intended to interlock with a headgear strap of headgear.

Frame 12 also includes at least one port 26 that allows for theintroduction of a pressure monitoring probe, or a separate gas such asoxygen (O₂) to be introduced (via a tube) into the interior of thebreathing chamber. The port 26 may be suitably covered by a port cap 28which is shown in the disconnected position in FIG. 1. As described andshown below, the port cap 28 may be formed as an integral part of thecushion 14.

FIG. 2 illustrates a patient's side or rear view of the mask assembly10. The face contacting portion of the cushion 14 preferably includes adouble layer, spaced wall configuration as described in U.S. Pat. No.6,513,526 assigned to ResMed Limited and incorporated herein byreference in its entirety. However, other cushion configurations such assingle or triple layer cushion configurations could also be employedwithout departing from the spirit and scope of the present invention. Inaddition, the cushion can be made of silicone, foam, gel, etc., orcombinations thereof.

FIG. 2 also illustrates an aperture 30 which communicates the inletconduit 18 of swivel elbow 16 to the breathing chamber. Surroundingaperture 30 is a generally circular support 32 formed as part of theframe 12. The support 32 forms a surface for an anti-asphyxia valvemembrane 34 (shown in detail in FIGS. 29-31). As described in moredetail below, the anti-asphyxia valve membrane 34 is positioned betweenthe support 32 and the swivel elbow 16.

FIGS. 3 and 4 illustrate front and rear exploded views of the maskassembly 10 shown in FIG. 1, without the swivel elbow 16 or itsassociated anti-asphyxia valve membrane 34. As shown in FIG. 3, theanti-asphyxia valve membrane 34 would be positioned adjacent circularsupport surface 36 of frame 12.

Frame 12 includes at least one and preferably a plurality of throughholes 40 which are intended to align with complimentary through holes 42provided on cushion 14. The cushion 14 is intended to be sandwichedbetween frame 12 and a cushion clip 44. The cushion clip 44 includes acorresponding number of fasteners or rods 46, e.g., provided along aflanged perimeter portion 48 of the cushion clip 44. The rods 46 areintended to align with and pass through the holes 42 and 40 of thecushion 14 and frame 12, respectively. Tips of rods 46 may besnap-fitted, melted or ultrasonically deformed so as to lock withrespect to apertures 40, thereby effectively sandwiching the cushion 14in place between the frame 12 and the cushion clip 44. Rods 46 mayinclude enlarged head portions that are tapered to allow penetrationthrough holes 40, 42 for assembly purposes. However, enlarged heads helpprevent disassembly of the frame, clip and cushion. Therefore, thecushion 14 may be permanently sandwiched in place, i.e., it is difficultto disassemble, which may be a benefit in a hospital or clinicalenvironment. However, the cushion could be structured to allow forselective disassembly, if desired. The cushion 14 includes a lateralperimeter flange 50 which may also be sandwiched or clamped between theframe 12 and the cushion clip 44. FIG. 3 also shows that the flange 50may provide a support surface for integral connection with port cap 28via bridge 29. In an alternative, the frame may be provided with therods, and the cushion clip could be provided with holes.

FIG. 4 best shows an inside surface 52 of the frame 12. Providedadjacent inside surface 52 is an upstanding wall member 54 whichpreferably extends along the entire perimeter to define the opening ofthe frame 12. The wall 54 provides support for the side walls of thecushion 14 as well as the interior side walls of cushion clip 44. FIGS.5-7 illustrate further assembly views of the frame 12, cushion 14 andswivel elbow 16.

FIGS. 8-12 illustrate further views of the frame 12 in isolation. FIG. 8shows that the frame 12 includes a notch 56 provided to facilitatepassage of bridge 29 (see FIGS. 3, 14 and 15) from the cushion side tothe frame side. The frame 12 also includes a plurality of protrusions orcastellations 60, e.g., 8 castellations, for the purposes of assistingwith retention of anti-asphyxia valve membrane 34 in elbow assembly (seeFIGS. 22, 23 and 29). As shown in FIG. 12, the frame 12 includes aperimeter flange 64 which defines a groove 66 by which the swivel elbow16 is secured to the frame 12.

FIG. 8 shows that the outrigger 22 includes legs 68, each of whichincludes a first end attached or otherwise provided to main portion ofthe frame 12, and a second end attached to or otherwise provided to theconnector clip receptacle 24. Preferably, the outriggers are formed asan integral piece with frame 12 and connector clip receptacle 24. Inaddition, the outriggers 22, e.g., legs 68, may resiliently bend, and/orresiliently flex about an axis 72, as indicated in FIGS. 8 and 9. Legs68 can also be structured so as to pivot in a hinge-like manner. Theprovision of this type of movement allows for certain benefits, e.g.,headgear strap self-tensioning and/or age/usage indication, more fullydescribed below. FIGS. 10-12 show top, bottom and side views of theframe 12, respectively. FIGS. 10 and 11 have bidirectional arrows whichschematically indicate the bending, pivoting and/or flexing of legs 68about axis 72.

FIG. 12A illustrates a perspective view of an alternative embodiment ofa frame 12′. The frame in FIG. 12A is very similar to the frame shown inFIG. 8, the only main difference being that frame 12′ includes 16instead of 8 castellations 60. The increased number of castellationshelps to reduce leak between the elbows and anti-asphyxia valvemembrane. However, the number of castellations may vary, and may, forexample, include any number above or below 16.

In another embodiment, one or both ends of legs 68 may include a portion70 about which the leg(s) may pivot, bend and/or flex. This would allowthe mask to assume various configurations, e.g., by moving the outriggervertically up or down with respect to the main body of the frame, asschematically illustrated by arrows in FIG. 9. Preferably, the legs 68should be parallel to one another to allow this adjustment, even thoughthe legs are seen as non-parallel (i.e., trapezoidal) in FIGS. 8 and 9.

FIGS. 13 through 15 illustrate various views of the cushion 14 inisolation, while FIGS. 16 and 17 illustrate various views of the cushionclip 44 in isolation.

FIG. 18 illustrates a partial cross-sectional and exploded view tohighlight the connection between frame 12, cushion 14, and cushion clip44. FIG. 19 is an assembled view of the components illustrated in FIG.18, while FIG. 20 is a perspective version of the exploded view shown inFIG. 18. As seen in FIGS. 18-20, frame 12 includes a bead-like member13, which helps to establish and ensure a reliable seal between frame 12and cushion 14. FIG. 19 shows bead member 13 embedded within cushion 14,although cushion 14 could also include a groove or aperture to receivebead member 13. Bead member 13 can also be seen in FIG. 4.

FIG. 21 illustrates an exploded view of a swivel elbow assembly 73,including swivel elbow 16, anti-asphyxia valve membrane 34 and swiveljoint 76. Swivel joint 76 includes first end 78 provided to inletconduit 18 and second end 80 provided to an air delivery tube incommunication with a source of pressurized breathable gas.

FIG. 22 illustrates an assembled view of the components shown in FIG.21, while FIG. 23 shows a cross-sectional view of the assembled swivelelbow assembly. As shown in FIG. 23, the anti-asphyxia valve membrane 34is preferably made of an elastomeric material. The swivel elbow 16includes a generally cylindrical inner tube 82. The cylindrical tube 82may provide a baffle between incoming air delivered via swivel joint 76and vented air, as indicated by the directional arrows in FIG. 23. FIG.23A shows an enlarged detailed view of a portion of the assembly shownin FIG. 23, while FIG. 23B is a partial cross-sectional viewillustrating the elbow as connected to frame with member 34 in position.

The anti-asphyxia valve membrane 34 includes a main body 84 which sealsand/or interlocks, e.g., via friction, with upstanding wall member 86formed as part of swivel elbow 16. Anti-asphyxia valve membrane 34 alsoincludes an aperture 88 (FIG. 21) which includes an inner shoulder 90(FIG. 23) for sealing against the outer surface of cylindrical tube 82of swivel elbow 16. The anti-asphyxia valve membrane 34 includes anouter shoulder 94 that prevents over-insertion of the membrane 34 withinthe swivel elbow 16 and allows for a snug fit with upstanding wallmember 86 of swivel elbow 16.

FIG. 24 illustrates a perspective view of swivel elbow 16 as seen fromthe patient's side. Air is delivered via inlet conduit 18 into domeportion 98 of swivel elbow 16. The swivel elbow includes a plurality offriction enhancing members 100 designed to ensure that the anti-asphyxiavalve membrane 34 stays frictionally engaged with the swivel elbow 16.

The swivel elbow 16 also includes a plurality of slots or apertures 102adjacent to which a plurality of tab members 104 are positioned, as seenin FIGS. 24 and 25. The tab members 104 are inclined (FIG. 24) so thatthey slightly expand or cam-out upon engaging flange 64 as shown in FIG.12, until overcoming the flange 64 and seating the tab members 104within groove or undercut 66, at which point the parts snap-fit toestablish a connection. The provision of apertures 102 helps to weakenthe swivel elbow 16 such that upon an attempt to disassemble the swivelelbow from the mask, the portion supporting the tab members or the tabmembers themselves deform and/or break away from the swivel elbow 16,thereby rendering the mask unusable, in which case a new mask would berequired for the patient. However, the selective weakening does notadversely impact the performance of the mask. Apertures 102 may also actas windows for breathing to atmosphere when the anti-asphyxia valvemember is de-activated.

FIGS. 26 through 28 illustrate various views of the swivel elbow 16 inisolation, while FIGS. 29 through 31 illustrate various views of theanti-asphyxia valve member 34 in isolation.

FIG. 28A illustrates another embodiment of the invention, including aswivel elbow 16′ which is similar to elbow 16 shown in FIG. 22. One ofthe main differences is that elbow 16′ includes a single aperture 20′provided for washout of exhaled CO₂ gas. Aperture 20′ may be fitted witha duck bill valve 23, which is known in the art.

FIGS. 28A-1 and 28A-2 illustrate an elbow according to a slightmodification, in which the aperture 20″ is raised and a valve member 23′is attached thereto.

In the embodiments of FIG. 28A and FIGS. 28A-1 and 28A-2, members 23,23′ constitute valve members. In another embodiment, members 23, 23′could constitute plugs that selectively seal the aperture. When the plugis in place, the aperture is sealed and the elbow is non-vented. Whenthe plug is removed, the aperture is exposed, thereby serving as anaccess port to receive a tube, e.g., naso-gastric in nature.

FIGS. 28B and 28C illustrate a swivel elbow 200 according to yet anotherembodiment of the present invention. Elbow 200 is intended to include ananti-asphyxia valve membrane (not shown) as described above. As shown inFIG. 28B, elbow 200 includes a dome portion 202 and a cylindrical centertube member 204. Upstanding wall 206 and tube member 204 are structuredto support anti-asphyxia valve member. Dome is provided with a pluralityof slots or apertures 208 and tab members 209, each of which function asdescribed herein. Provided to a peak portion of the dome 202 is a tube210 having a first end 212 that extends through central aperture ofanti-asphyxia valve membrane. Tube 210 includes a second end (notvisible) which is integrally connected or provided to the peak of dome202. As such, dome will include only a single aperture, like that shownin FIG. 28A.

As shown in FIG. 28C, tube member 204 includes an aperture 214 which isprovided at a base of tube member 204. Aperture 214 in this example iseye-shaped, although it could have any shape.

FIGS. 28D-28H illustrate an elbow 300 according to another embodiment ofthe present invention, which is similar to the embodiment of FIGS. 28Band 28C. As shown in FIGS. 28D and 28E, dome portion 302 includes aplurality of concentric, raised rings 303. As shown in FIGS. 28E-28H,center tube portion 304 extends just outside dome portion 302, but endsbefore reaching the lower end of the elbow housing which helps with CO₂gas washout. An inner tube 310 extends from the top of the dome portion302 and past the end of the elbow housing. The top 311 of the inner tube310 is profiled, as shown in FIGS. 28E-28G. The opening 313 leading toatmosphere is of smaller cross-section than the central portion 315 oftube 310. A transition 317 is formed between the opening 313 and centralportion 315. Transition, e.g., may take the form of a tapered conicalsection. Like the embodiment of FIGS. 28B and 28C, central tube 302includes an aperture 314 to allow the flow of gas from the air deliveryconduit to the inside of tube 302, which helps to lower impedance.

FIGS. 31-A to 31-I illustrate a mask assembly 10 according to anotherembodiment of the present invention. FIG. 31-A is a front view of themask assembly 10, while FIG. 31-B is a side view of mask assembly 10.The illustrated reference numbers denote components or parts that havebeen described in relation to one or more embodiments described above,e.g., FIG. 1.

Mask assembly 10 includes a swivel elbow 16′ that is more specificallydiscussed in relation to FIGS. 31-C-31-F. Elbow 16′ includes an inletconduit 18 (FIG. 31F) having a hose end 18 a with a plurality ofresiliently deformable tabs 18 b that are structured to allow selectiveattachment to and detachment from a swivel 76. Each tab 18 b includes aradially extending protrusion 18 c that locks in place within aninterior of groove 76 a of swivel 76. FIG. 31-E shows the assembledposition. The elbow 16 is preferably made from a polyester, e.g.,natural POCAN®, a Bayer product, although other materials are possible.The swivel 76 may be made of clear polycarbonate, although othermaterials are possible. This assembly allows for removal of the hose(not shown) without compromising the integrity of the frame. Theinternal geometry and functioning of the dome portion of elbow 16′ issimilar to or the same as that described above or in relation to FIGS.28D-28H. Elbow 16′ may be used in conjunction with anti-asphyxia valvemember 34′, as shown in FIGS. 31-G to 31-I, whose function is similar tothe member 34 described in relation to FIGS. 29-31.

FIG. 32 illustrates a headgear clip 106 according to one embodiment ofthe present invention. The headgear clip 106 includes a first end 108for engagement with headgear clip receptacle 24 shown in FIGS. 1 and 2and a second end 110 for engagement with a headgear strap of headgearassembly. The first end 108 includes first and second arms 112 which maybe flexed toward one another in the plane of the paper so as to squeezeinto receptacle 24. The receptacle 24 includes an appropriate protrusionor catch 114 (FIG. 1) in a locked position. To unlock the arms 112 fromthe catch 114, each receptacle 24 includes a pair of opposed arm members116 which may be pressed toward one another to thereby compress the arms112 towards one another, thereby placing the headgear clip 106 in aposition such that it can be removed from the outrigger 22 and thereceptacle 24. The geometry of clips 106 allows them to spring out ofreceptacles 24 when opposing arms 116 of receptacle are pressed. Eachheadgear clip 106 includes a central leg 118 including a groove 120which is designed to receive a protrusion 122, shown in FIG. 2. FIG. 33is a front perspective view of the headgear clip 106, while FIG. 34 is arear view of the headgear clip 106. Of course, different headgear clipand clip receptacles can be used instead.

FIGS. 34A and 34B illustrate another embodiment of a headgear clip 106′which is similar to the clip 106 shown in FIGS. 32-34. Several changeshave been made which may reduce manufacturing costs, facilitatemanufacture, and/or enhance performance.

FIG. 35 illustrates a first embodiment of headgear 124 according to thepresent invention. Headgear 124 may be manufactured by starting with asubstantially flat piece of appropriate material, such as polyester loopmaterial, Breathoprene®, leather, cloth, plastic, etc., and thencutting, scoring or weakening the headgear along predetermined cut lines126 whereby the headgear 124 may be repositioned to approximate theshape of the patient's head. The headgear 124 may include side straps128 and front strap 130. Side straps 28 may be created with a singleslit 126. Also, in this example, main body 127 of strap has anappropriate amount of slits, e.g., 2-5 slits or more, to optimizecoverage and stability of the headgear 124 or patient's head. Generallyspeaking, each of slits 126 expand in use to form a plurality of openspaces 126′, when the headgear is placed on the patient's head.

The positioning of the headgear 124, including the side straps 128 andfront strap 130, in relation to the mask assembly 10 and the patient'shead is shown in FIG. 36. FIG. 37 illustrates a rear perspective view ofthe patient's head with the headgear 124 provided thereto. This positioncups the occiput of the head to thereby create stability. As can be seenfrom FIGS. 36 and 37, the headgear includes a plurality of fold lines132 which are created due to repositioning of the headgear 124 from theposition shown in FIG. 35 to the position shown in FIGS. 36 and 37.These predetermined fold lines 132 are acceptable for use in a clinicalor hospital environment. However, they do not adversely affect theperformance of the headgear 124.

FIG. 38 illustrates a second embodiment of headgear 134 according to thepresent invention. Headgear 134 includes side straps 136 and front strap138. Again, the headgear 134 may be manufactured by providing a flatpiece of material appropriate for use as headgear on a patient. Eachside strap 136 is created by cutting the material along a predeterminedcut line 140. The headgear 134 may include a plurality of additional cutlines 142, which creates a net-like configuration on the patient's head,as shown in FIGS. 39 and 40. Each cut line 142 forms an open area 142′,to effectively cup the patient's head. Open areas 142′ provide forventilation of the patient's head. Open areas 142′ may be in the shapeof a polygon, e.g., a triangle or a diamond. Of course, other headgeararrangement may also be used to support mask assembly on the patient'shead.

FIG. 41 illustrates headgear 400 according to another embodiment of thepresent invention. Headgear includes side straps 402, 404 and a topstrap 406, such that it can be used with the mask shown in FIG. 1.Headgear 400 includes cutouts 408 which help with ventilation and ensurethat the headgear is fully retained. Cutouts 408 help headgear toconform to the patient's head. Headgear 400 includes a unidirectionalstretch back piece 410. Cutouts 408 may be separated by a divider 409which may be detachably connected, e.g., via stitching and/or Velcro®,etc. FIG. 42 shows the headgear in position on a model patient's head.

Disposable Characteristics

The mask assembly 10 is intended to be used by a single patient for alimited life span and not reused on further patients. This removes thetime and expense of cleaning and reassembling the product. In addition,it removes the difficulties found when components can be lost orassembled incorrectly. For safety reasons, and to avoid cross-infection,the product should have both the function and/or aesthetics of adisposable product in order to alert the user and discourage extendeduse or use on more than one patient.

The mask assembly has been configured so as to satisfy needs of aclinical or hospital staff. This has been achieved while retaining maskperformance desired by patients, which performance includes comfort,minimized leaks, etc., and therefore facilitates patient compliance withtreatment.

The mask appears to be disposable from the feeling that it is lessdurable than a reusable mask. The mask is purposely prone to distortionthrough handling because it is made from materials that have an expectedservice life, e.g., of about 7-14 days, and preferably no more than 7days. In addition, the mask has the characteristic of displaying its“age”, e.g., via stress whitening (described in more detail below), andtherefore provides an indication to users of the mask system's aging andapproaching end-of-life. This aging characteristic is in contrast toprior art disposable masks that typically, without warning, fail in use,for example, when they are stressed while undergoing the procedures ofdisassembly, washing, assembly or fitting.

The mask system provides a warning to users of approaching end-of-life.In addition, the aging characteristic is intended to serve the safetyfunction of dissuading cross-patient use—the second intended user isdisinclined to select or don a used mask. In this way, the agingcharacteristic facilitates the control of cross-infection and istherefore particularly useful in a clinical multi-patient environment.

Frame

The frame may be formed by polypropylene, polyethylene, PETE, etc., andmay be manufactured using a molding process, e.g., injection molding.Preferably, the frame is made of polypropylene with a thin walledsection (approximately 0.25-1 mm, preferably about 0.5 mm) that gives itthe characteristic of being more flexible than typical multi-use maskframes. Flexibility is desirable because it gives the feeling of beingless durable.

In the present embodiment, aging is achieved through the exhibition of“stress whitening.” Stress whitening occurs as a result of excessive orrepeated deformation of polypropylene and other materials such aspolyethylene or PETE. Such excessive and/or repeated deformation willeventually cause the frame material to turn white, ergo the term “stresswhitening.”

The present embodiment incorporates the characteristic to display stresswhitening through an appropriate combination of design and/orcomponents. For example, the wall thickness and stress loading can bedesigned so as to control stress whitening to occur in those portions ofthe mask which are most visible to the clinician. For example, theoutriggers 22, e.g., legs 68, shown in FIG. 8 may be designed such thatthey will deform when the headgear is fitted and as such they willexhibit stress whitening with use. As described above, the outriggers 22include legs 68 which are intended to bend, flex or pivot about axis 72,as shown in FIGS. 8 and 9. Repeated and/or excessive such movement cancause stress whitening. In other embodiments, stress whitening can beused to form a readable text message (e.g., “replace mask” or “discard”)which appears only after stress whitening has occurred. Of course, themask could be designed such that stress whitening occurs in otherlocations.

Stress whitening will give the visual indication that the mask systemhas been used. If the mask frame is configured so that the developmentof stress whitening (e.g., increase in intensity or area displayingstress whitening, or both) occurs as a result of repeated deformationduring use, then the mask will also provide a visual indication of agingand approaching end-of-life.

The development of stress whitening will also serve to provide a safetywarning to users. By warning of imminent end-of-life, it therebycautions against use of the mask where it can be expected to fail inuse.

Although the mask may exhibit some degree of stress whitening, stresswhitening alone will not cause breakage, thereby causing a catastrophicfailure. By contrast, the state of the prior art is that masks exhibit atendency toward unexpected catastrophic failure, e.g., a componentsnapping, without warning.

A complimentary but independent feature further enhances the frame'sdisposable characteristic. Some and preferably all components areconfigured to assemble with a one-way snap action. Once the maskframe/vent and anti-asphyxia valve and cushion components are assembled,they cannot be disassembled without breakage occurring. Further,disposable characteristics of a mask system are that the mask cannoteffectively be cleaned as it cannot be disassembled which is a furtherindication that it is disposable, it is low cost, it has white headgearthat is likely to show dirt, grime and wear, and/or it is appropriatelylabeled.

The frame may include a headgear strap with a self-tensioning feature.This will facilitate a clinical party (i.e., non-patient) fitting of themask without assistance of the patient. The flexible legs 68 that extendfrom the frame include attachment points for the lower two headgearstraps. The flexibility allows for the legs to fold towards the back ofthe patient's head and thereby provide extra length to the headgearstraps/flexible arms combination when fitting the mask system, thusallowing for the headgear to be located over the patient's head. Then,when the mask and headgear are in place, the legs spring forward, i.e.,away from the patient's face, thereby placing some tension to theheadgear mask assembly. This helps to avoid the need for cooperation ofthe patient.

Cushion

The cushion 14 disclosed herein may adopt at least some of the samegeometry as is available in the current Mirage® Full Face mask, whichincludes an upper membrane and an underlying profile. See U.S. Pat. No.6,513,526 incorporated herein by reference in its entirety.

The cushion 14 is attached to the frame 12 by sandwiching the cushionbetween the cushion clip 44 and the frame 12. However, the cushion 14may be attached to the frame 12 using mechanical (e.g., tongue andgroove) and/or adhesive techniques.

In an alternative assembly, the cushion can be molded directly to theframe, e.g., via over-molding, with the frame being made ofpolypropylene and the cushion being made of TPE.

Anti-Asphyxia and/or Back Flow Reduction Valve

The anti-asphyxia valve situated in the swivel elbow 16 functions asboth an anti-asphyxia valve and a back flow reduction device. The valveis permanently assembled from three components—the elbow, the valvemembrane 34 and the frame 12. To assemble, the membrane 34 is aninterference fit with the elbow 16 (see, e.g., FIGS. 23, 23A, 23B) whichis then a permanent snap fit to the frame 12. The snap fit includes anundercut on the frame, e.g., groove 66 in FIG. 12, which connects withsix tab members 104, for example, on the elbow 16.

When the flow generator is switched off, or in the case of malfunctionsuch as a power cut, the valve membrane 34 sits in the original orunextended position. The edge of the membrane forms a seal against theinner tube 82 of the elbow 16 and thus prevents flow from the maskreaching the inlet conduit 18 and consequently the flow generator. Thus,the valve prevents gas flow back to the flow generator which isparticularly useful in circumstances where O₂ is ported into the mask.Any O₂ that is supplied to the mask cannot reach the flow generator,i.e., the valve acts as an O₂ divertor valve (ODV) and removes apotential fire hazard. In addition, see U.S. Patent ApplicationPublication 2004/0094157 A1 assigned to ResMed Limited and incorporatedby reference in its entirety.

In the unpressurized state, air reaches the mask through the six slots102 (FIGS. 23B, 24 and 25) in the elbow 16 which connects with thecircular inlet in the frame. Ambient air is channeled between the lowersurface of valve member 34 and surface 36 (FIG. 3) of frame 12. Thus,the valve is also acting as an anti-asphyxia device. This embodiment hasan advantage over ResMed's anti-asphyxia valve mentioned above in thatit closes the flow to the inlet conduit 18. This prevents air from berebreathed from the inlet conduit 18.

When the flow generator is switched on and pressure is applied, themembrane 34 extends from its original position and forms a seal againstthe circular inlet (e.g., surface 36 in FIG. 3) of the frame 12. Thispressurized air from the inlet conduit 18 can flow around the elbowinner tube 82 and directly through the circular inlet of the frame. Theinner shoulder 90 may separate from the end of tube 82, as shown inphantom in FIG. 23A. In this position, the valve member is configuredsuch that it may provide an audible noise, e.g., a whistle. This mayprovide comfort or a positive feedback signal to the patient/clinicianthat the device is assembled properly and/or that pressurized gas isbeing properly channeled. The audible signal, e.g., whistle, can becreated by vibrations in a manner similar to that created when playingthe reed of a musical instrument. Alternatively, a small gap may bedesigned to create the whistle effect. The device, e.g., theanti-asphyxia valve, may be arranged such that a noise is created if thesystem is not correctly assembled, to thereby provide a warning to theuser or clinician. In general, the mask can be designed to include ornot include noise, depending on preference.

This design achieves a lower profile elbow, which is desirable both foraesthetic reasons and it improves the stability of the mask. Anotherfactor to consider when designing the elbow is the entry impedance ofthe mask. It is desirable to minimize impedance in order to preventpressure swings occurring during breaths.

The lower profile elbow is achieved by a number of factors. Firstly, theelbow acts as the housing for the membrane and the valve is placed atthe interface of the elbow in the frame. This reduces the number ofcomponents that are required (and associated manufacturing costs) aswell as removing the bulk of a further interface. Secondly, the inletconduit 18 is at an angle from the mask of greater than 90°, e.g.,100°-120°. Thirdly, the diameter of the inlet cavity has been increased.This increases the cross-sectional area presented to the inlet flow (andthus reduces the entry impedance) for a given elbow inlet angle.

The valve is physically larger than the existing ResMed anti-asphyxiavalve mentioned above to achieve a reduced impedance in the elbowcompared to the currently available ODV.

Mask Vent

The mask vent is incorporated in the elbow. Existing ResMed full facemasks have their vents incorporated in the mask frame.

Inadvertent leak is virtually zero due to the configuration of the ventand anti-asphyxia valve. This performance is achieved partly byconfiguring the anti-asphyxia valve to include a relatively soft part,e.g., membrane 34 made, e.g., of silicone, to seal between the frame andthe swivel elbow.

When a vented mask is adopted to be used with a ventilator there is arequirement to calibrate the vent. This process typically requiresblocking of all the pathways to atmosphere so that the path toatmosphere occurring at the vent may be isolated and therebycharacterized.

By putting the vent in the elbow it is relatively easy to block theorifice joining the mask chamber and the elbow downstream of the vent soas to achieve the required isolation. This configuration avoids thedifficult to perform blocking of the large path to atmosphere thatoccurs at the mask aperture, i.e., the mask chamber entry point whichreceives the patient's face. A plug may be used to block the orificebetween the elbow and the mask chamber, but it may be also easilyachieved in the clinical setting by placing a finger over the orifice.

This is an advantage in a situation as compared to the prior art, whichincludes three sizes of frames with a vent in each frame, therebyrequiring different tools for each frame/vent for calibration. Thisembodiment of the invention simply has a single elbow to calibrate forflow, independent of the mask frame size.

The anti-asphyxia valve may be adopted for use in a multiple use fullface mask as it is made from silicone where it will be robust, washableand capable of reassembly. The anti-asphyxia valve is then a commonpart, requiring less inventory and there will be no need to develop anew anti-asphyxia valve for a new face mask.

Frame Port and Port Cap

The frame port cap is configured to meet clinical needs. The port cap isintegrated into the cushion configuration, which allows the port cap tobe formed at the time of cushion manufacture, thereby eliminating theneed for separate manufacturing. This allows for a one molding operationto make the cushion and mask components. It also allows the port cap topass through manufacturing and distribution chain as one component withthe cushion. This simplifies handling and inventory logistics, andreduces manufacturing and warehousing costs.

The location of the port cap in relation to the cushion are such thatwhen the cushion is attached to the frame, the port cap is convenientlypositioned to be attached to the frame port.

These features are particularly welcome in the clinical setting wherethere is need to frequently attach and detach a port cap (e.g., whenattaching or detaching lines to the frame port or for the measurement oftreatment pressure, servo control of flow generator or deliveringtreatment gas such as O₂). With the port caps attached to the cushion itis always conveniently available to be attached to the frame port.

In addition, the port cap has one or more large grip wings to facilitateconvenient manipulation. A problem identified by the inventors is thatthe typical small port caps supplied with prior art masks are anannoyance to the regular clinical user. Grip wings may be supplied for agroup of port caps or individually associated with each port cap.

Preferably, the port and port cap are located at the bottom of the maskso as to avoid interference with other components of the mask assembly,as described in U.S. Pat. No. 6,439,230, assigned to ResMed Limited andincorporated herein by reference in its entirety. Of course, the portand port cap could be located in other convenient positions around themask frame. In addition, multiple ports and caps could be provided tothe same mask.

Headgear

The headgear performs in a manner that contributes to the systems agingcharacteristic. This performance is achieved by use of material thatgives a display of its accumulation of grime, i.e., soiling. The chosenmaterial accumulates and displays its accumulation of grime, e.g., byvisual and tactile signals. Preferably, the headgear when first broughtinto service is generally white or other a light shade of color.

In addition to the objective visual signal, the aging characteristicachieved through the perception of soiling will provide a usefulpsychological signal. Potential users will not want to don a seriouslysoiled headgear while a clinical staff will be prompted to choose afresh mask system for patients especially when fitting a patient new tothe mask.

Grime may be attributable to skin, sweat, oils, facial secretions, etc.The aging characteristic may be incorporated into the headgear and/ormask frame in such a way that the headgear or mask frame exhibits agedue to exposure with such sources of grime. In other words, grime mayprovide a visual indication on the headgear frame to signal theclinician that it is time to replace the mask system.

In another alternative, the aging characteristic can be provided withheadgear which frays or otherwise decomposes after repeated use beyondthe nominal set limits.

The headgear strap configurations allow for more consistent location ofstraps under the patient's ear and thereby avoid the annoying contact ofthe strap with the lower portion of ear.

Headgear may be configured from a die cut side piece, e.g., a laminatedmaterial which in its unassembled form is shaped to minimize waste andthus reduce costs/control. The waffle pattern, when expanded, will allowfor expansion and correct placement on the head. This design achieves athree-point fitting configuration. A two-dimensional piece of materialis used to achieve a three-point headgear which achieves the performanceof a four or five-point headgear. This allows for placement of the topstrap to follow a line which is low on the ears and resembles what isachievable with a four strap headgear, which allows for desirabledistribution of forces but with the convenience of one top strap.

Headgear Clip

The headgear clip mechanism includes a housing which incorporatesrelease tabs and that is formed as part of the frame. A headgear clip isspring-fit into the receptacle on one side and acts as an attachmentpoint for the headgear on the other side. The headgear attachment sidehas two slots. The first slot 111 (FIGS. 32-34), closest to the mask, isa fully formed slot through which the headgear is threaded. The secondslot 113, closest to the headgear has large shaped tabs 115 formed onone side, between which a gap G exists. The gap G and the tapered shapeof the tabs allows the headgear to be connected through the second slotby pulling down through the tabs. This assembly technique is muchsimpler than threading.

Further benefits of the clip design are that the clip is very largewhich makes it easier for manipulation. The tabs 116 (FIG. 1) to releasethe clip are operated from the top and bottom which facilitates the userconfiguration. Further, the tabs 116 form part of the frame, rather thanpart of the clip. Therefore, the tabs do not slide with the clip whichmakes single handed operation easier.

The headgear clip may include a ladder lock and lead-in design. Theheadgear clip may serve as a quick release mechanism, i.e., the sprungrelease of the clip is a quick release mechanism. It has an exaggeratedtactile finger tab to make it easier to find should there be a need forrapid response quick release.

The headgear clip allows for quick manual assembly which serves both asa manufacturing aid and a benefit to customers as it allows for apresentation of a fully assembled product and benefits a clinicalsetting as it allows for quick reassembly when required.

Summary—General Effects of Preferred Embodiments

Hospital and fully featured hospital use is characterized by severalfactors: single patient use, clinician requirements, and/or adesirability to discourage reuse.

Ease of fitting may be achieved via a headgear spring/outrigger design.Ease of assembly prevents incorrect assembly and protects frominterference and tampering. Disassembly is prevented between the cushionand frame since they are permanently connected. The elbow is snapped tothe frame via a one-way snap, which cannot be disconnected withoutdestroying or breaking the elbow and/or frame. The ports cap is formedas an integral portion of the cushion, thereby preventing its loss ordetachment.

The mask is designed to discourage reuse because there is no method ofefficient cleaning that is possible as there is no access to theanti-asphyxia valve. Moreover, the mask displays evidence of use, e.g.,via stress whitening and distortion under force. Stress whitening may beachieved by some combination of material, wall section dimensions,geometric form and/or use of a yielding flexible part. The materials mayinclude polypropylene, polyethylene or PETE, and may be made by molding,such as injection molding or they may be vacuum formed. The stresswhitening may be provided via the outriggers although the top support ofthe frame, the forehead support, port cap, etc. may also be used toexhibit stress whitening. Moreover, a living hinge could also be used todisplay evidence of use.

Other alternatives to stress whitening include snapping via a one-wayconnection, to thereby prevent or inhibit reuse. Other possibleindicators include exposure to air, O₂ or grime, exposure tocondensation (moisture indicators), CO₂ detectors, etc.

The mask frame is intended to look disposable and non-durable via one ormore of the following criteria: material choice, color (headgear iswhite, frame could also be white). Headgear could be cardboard with aplastic interior, material thickness, simple construction and/or anexposed construction method. The mask feels disposable, e.g., the frameis flexible and will deform with predetermined and/or repeatedapplication of force.

The port and cap structure is advantageous since it is an integralcomponent with the cushion, and cannot come apart from the assembly.Therefore, the port cap cannot be lost since it is attached to thecushion. This allows for lower manufacturing cost as the cushion and capare one component rather than two. This also prevents cross-patient use.

The port cap includes one or more large grip tabs, which are easier tooperate, particularly for clinicians. The large grip tabs allow for easylocation. The grip tabs are visible, and show whether they are on oroff, and their operation is obvious to inexperienced users, therebyavoiding the error of cap being left off.

The port cap is self-locating, meaning that the cap stays close to theport when removed, but requires little dexterity to place the port capback onto the port, and does not require visual affirmation sinceaffirmation can be provided via tactile means.

The port cap is positioned at the bottom of the frame, which is near thenares, thereby providing an advantage for the supply of oxygen. The portcap is not susceptible to being disturbed by movement of the patient'shead. The port cap allows an air inlet tube and swivel to rotate freely.The most common position of the air inlet tube is always away from thebottom, and the smaller tubes can be easily routed along the tube ascommonly occurs.

Alternative embodiments include a living hinge cap molded from theframe. This had the advantage of displaying evidence of use, e.g.,stress whitening.

In still further embodiments, a barbed head may be pulled through theframe or cushion wall, with the barbed head sealing against the frame.The port cap can be molded with a thin strap directly to either thecushion or the frame. The port cap may be sandwiched between the cushionand frame, which decreases the chances that the port cap can be lost.The port cap can be co-molded with the frame. The port cap can be moldedintegrally with the anti-asphyxia valve or the vent or any elastomericcomponent. The port cap can be purposely made to break off with use todisplay hospital use, to thereby convey the disposable nature of themask. Alternatively, the port cap may develop a cut end with overuse.

The above described self-tensioning feature facilitates fitting of themask assembly to the patient. The self-tensioning spring provideselasticity when required, e.g., when initially taking the headgear overthe head. This allows a larger degree of opening when fitting. Inaddition, it could be used with non-elastic headgear, and isparticularly suitable for a third party/clinician fitting.

The self-tensioning aspect provides a spring to give some tension wheninitially fitted before tightening the straps. This prevents the strapsfrom simply flopping and prevents the tangling of straps.

The self-tensioning aspect provides a visual indication that straps arenot tight or tensioned. In a further embodiment, a tension indicator maybe provided, which displays the amount of tension either by angle (thiscould be whilst on the patient) or with permanent deformation forclinical evaluation after patient use.

The self-tensioning aspect keeps the headgear from tangling away fromthe patient, and may include broad attachment points, which maintainstrap alignment and does not twist.

The self-tensioning aspect also may display evidence of use, e.g., viastress whitening upon use. Evidence of use may also be demonstrated viause of various combinations of material, thickness and geometric form.The outriggers may also creep with use to a point at which it does notregain form after patient use.

In alternative embodiments, the outriggers could be used on reusablemasks. The headgear clips can be snapped into use under certain tension.This has an advantage of maintaining form and a larger degree of openingbut does not act as a spring. This may give a strong indication of useby not maintaining form after first use, and encourage the product to bethrown away after single patient use.

The outrigger assembly may include a living hinge, which may beadvantageous from the aspect of keeping form in larger degree of openingbut does not act as a spring. This would give a strong indication of useby not keeping form after first use, and encourage the product to bethrown away after single patient use. This would show use at the hingepoint.

In other alternatives, a self-tensioning spring could be attached toheadgear rather than the frame. In addition, a tension indicator maydisplay the amount of tension either by angle, whilst on the patient, orwith permanent deformation for clinical evaluation after patient use.The hinge could be part of a cushion or a captive part of the cushionframe interface rather than part of the frame. The hinge could beincorporated into the designs of other existing disposable and reusablemasks.

Headgear according to the present embodiments include several featuresand/or advantages. For example, the headgear is manufactured using astrip design, which is the lowest volume for manufacture, meaning lowwasted or inefficient use of materials. The design expands from aone-dimensional strip in manufacture to a three-dimensional cup in use.

The process for making the headgear can be from a single stamp or slitwithin the perimeter of the strip. The headgear need not cover much ofthe head, is cool and is unobtrusive. The headgear achieves a simple yetstable design. Different colors can be provided on each side of thematerial for a visual clue as to the part which is facing towards andaway from the patient, which allows for ease of assembly andnon-tangling of the strap components.

Alternative materials for the headgear include foam, silicone and/orbreathable materials. The material can be elastic or non-elastic, ofvarying stiffnesses in different directions. Further, separate stripscan be joined with varying stiffnesses. This will allow fine tuning ofthe elasticity of individual straps of the headgear. Various stiffnessescan also be achieved by sticking VELCRO® tapes over part of the headgearor by providing cross-stitching, etc. The headgear can also bemanufactured by forming a number of individual components, laying themnext to each other and then joining them via stitching, gluing, etc.

While the invention has been described in connection with what ispresently considered to be the most practical and preferred embodiments,it is to be understood that the invention is not to be limited to thedisclosed embodiments, but on the contrary, is intended to cover variousmodifications and equivalent arrangements included within the spirit andscope of the invention.

1. (canceled)
 2. A mask assembly configured to deliver positivelypressurized breathable gas to a patient, the mask assembly comprising: acushion configured to sealingly engage the patient's face; a frameremovably secured to the cushion so that the cushion and the frame atleast partly form a breathing chamber, the frame comprising a projectionthat becomes embedded within the cushion when the cushion is attached tothe frame to at least partly form the breathing chamber to maintain aseal between the cushion and the frame; and an outrigger assemblyattached to the frame and including a clip receptacle, the outriggerassembly being configured to resiliently flex around two intersectingaxes so that the clip receptacle has two degrees of freedom relative tothe frame and returns to a neutral position in the absence of a forceacting on the clip receptacle.
 3. The mask assembly of claim 2, whereinone of the two intersecting axes is oriented so that when the outriggerassembly is resiliently flexed around said one of the two intersectingaxes, the clip receptacle moves in the anterior and posteriordirections.
 4. The mask assembly of claim 3, wherein the other of thetwo intersecting axes is oriented so that when the outrigger assembly isresiliently flexible around said other of the two intersecting axes, theclip receptacle moves in the superior and posterior directions.
 5. Themask assembly of claim 2, wherein the frame includes a centrally locatedupper extension configured to engage the patient's forehead when thecushion engages the patient's face.
 6. The mask assembly of claim 5,wherein the centrally located upper extension comprises a headgear strapreceptacle.
 7. The mask assembly of claim 2 further comprising arotatable elbow attached to the frame.
 8. The mask assembly of claim 7,wherein the rotatable elbow comprises a swivel connection configured toconnect to an air delivery tube.
 9. The mask assembly of claim 7,wherein the rotatable elbow comprises an anti-asphyxiation assembly. 10.The mask assembly of claim 2 further comprising a gas washout vent. 11.The mask assembly of claim 2 further comprising headgear with a headgearclip configured to be received by the clip receptacle to attach theheadgear to the frame.
 12. The mask assembly of claim 2, furthercomprising: a gas washout vent; headgear with a headgear clip configuredto be received by the clip receptacle to attach the headgear to theframe; and a rotatable elbow attached to the frame, wherein therotatable elbow comprises a swivel connection configured to connect toan air delivery tube, wherein the rotatable elbow comprises ananti-asphyxiation assembly, wherein one of the two intersecting axes isoriented so that when the outrigger is resiliently flexed around saidone of the two intersecting axes, the clip receptacle moves in theanterior and posterior directions, and wherein the other of the twointersecting axes is oriented so that when the outrigger is resilientlyflexible around said other of the two intersecting axes, the clipreceptacle moves in the superior and posterior directions, wherein theframe includes a centrally located upper extension configured to engagethe patient's forehead when the cushion engages the patient's face, andwherein the centrally located upper extension comprises a headgear strapreceptacle configured to receive a headgear strap of the headgear.
 13. Amask assembly configured to deliver positively pressurized breathablegas to a patient, the mask assembly comprising: a cushion configured tosealingly engage the patient's face; a frame removably secured to thecushion so that the cushion and the frame form a breathing chamber, theframe comprising a projection that becomes embedded within the cushionwhen the cushion is attached to the frame to form the breathing chamberto maintain a seal between the cushion and the frame; and an outriggerassembly comprising a pair of legs attached to the frame and terminatingat a clip receptacle, each of the pair of legs being configured toresiliently flex around two intersecting axes so that the clipreceptacle has two degrees of freedom relative to the frame and returnsto a neutral position in the absence of a force acting on the clipreceptacle.
 14. The mask assembly of claim 13, wherein one of the twointersecting axes is oriented so that when the pair of legs areresiliently flexed around said one of the two intersecting axes, theclip receptacle moves in the anterior and posterior directions.
 15. Themask assembly of claim 14, wherein the other of the two intersectingaxes is oriented so that when the pair of legs are resiliently flexiblearound said other of the two intersecting axes, the clip receptaclemoves in the superior and posterior directions.
 16. The mask assembly ofclaim 13, wherein the pair of legs are parallel to each other.
 17. Themask assembly of claim 13, wherein the pair of legs are resilientlyflexible relative to the clip receptacle.
 18. The mask assembly of claim13, wherein the pair of legs are resiliently flexible relative to theframe.
 19. The mask assembly of claim 13, wherein the frame includes acentrally located upper extension configured to engage the patient'sforehead when the cushion engages the patient's face, the centrallylocated upper extension comprising a headgear strap receptacle.
 20. Themask assembly of claim 13 further comprising a rotatable elbow attachedto the frame, the rotatable elbow comprising a swivel connectionconfigured to connect to an air delivery tube and comprising ananti-asphyxiation assembly.
 21. The mask assembly of claim 13 furthercomprising a gas washout vent.
 22. The mask assembly of claim 13 furthercomprising headgear with a headgear clip configured to be received bythe clip receptacle to attach the headgear to the frame.
 23. The maskassembly of claim 13, further comprising: a gas washout vent; headgearwith a headgear clip configured to be received by the clip receptacle toattach the headgear to the frame; and a rotatable elbow attached to theframe, the rotatable elbow comprising a swivel connection configured toconnect to an air delivery tube and comprising an anti-asphyxiationassembly, wherein one of the two intersecting axes is oriented so thatwhen the pair of legs are resiliently flexed around said one of the twointersecting axes, the clip receptacle moves in the anterior andposterior directions, wherein the other of the two intersecting axes isoriented so that when the pair of legs are resiliently flexible aroundsaid other of the two intersecting axes, the clip receptacle moves inthe superior and posterior directions, wherein the pair of legs areparallel to each other, wherein the pair of legs are resilientlyflexible relative to the clip receptacle, wherein the pair of legs areresiliently flexible relative to the frame, the frame includes acentrally located upper extension configured to engage the patient'sforehead when the cushion engages the patient's face, the centrallylocated upper extension comprising a headgear strap receptacleconfigured to receive a headgear strap of the headgear.